GI quizOnline version GI quiz on anatomy and physiology by Stephen 1 Which structure prevents reflux of stomach acid into the oesophagus? a Upper oesophageal sphincter b Ileocecal valve c Pyloric sphincter d Lower oesophageal sphincter 2 Which epithelial type normally lines the oesophagus? a Transitional epithelium b Cuboidal epithelium c Stratified squamous epithelium d Simple columnar epithelium 3 Which muscle type is found in the upper third of the oesophagus? a Smooth muscle b Cardiac muscle c Skeletal muscle d No muscle present 4 What is the main function of peristalsis in the GI tract? a Propelling food along the GI tract b Neutralising stomach acid c Mixing intestinal contents locally d Absorption of nutrients 5 Which muscle layer is unique to the stomach and helps mix food into chyme? a Transverse b Circular c Oblique d Longitudinal 6 Which cells in the stomach secrete hydrochloric acid (HCl)? a Enteroendocrine cells b Parietal cells c Mucous cells d Chief cells 7 Which substance produced in the stomach is required for vitamin B12 absorption? a Intrinsic factor b Histamine c Gastrin d Pepsin 8 Which bacterium is the most common cause of gastric ulcers? a Streptococcus pyogenes b Staphylococcus aureus c Escherichia coli d Helicobacter pylori 9 Which secretion helps protect the stomach lining from acid and digestive enzymes? a Gastrin b Mucus c Pepsin d Hydrochloric acid 10 A student experiences reflux symptoms during exam stress. Which physiological change is most likely responsible? a Increased gastric acid secretion b Increased mucus secretion c Reduced gastric motility d Reduced gastric acid secretion Feedback 1 The lower oesophageal sphincter (LES) prevents reflux of acidic stomach contents into the oesophagus. Dysfunction of the LES can lead to gastro-oesophageal reflux disease (GERD), causing heartburn and oesophageal irritation. 2 The oesophagus is lined with stratified squamous epithelium, which protects against abrasion from swallowed food. At the gastro-oesophageal junction (Z-line) it changes to simple columnar epithelium of the stomach. Barrett's Oesophagus can cause this to change. 3 The oesophagus transitions from skeletal muscle in the upper third, to mixed muscle in the middle, and smooth muscle in the lower third. This allows swallowing to begin voluntarily and then continue involuntarily through peristalsis. 4 Peristalsis is a coordinated wave of circular muscle contraction that propels food along the GI tract. It is coordinated by the myenteric plexus of the enteric nervous system. 5 The stomach has three muscle layers: longitudinal, circular, and oblique. The oblique layer is unique to the stomach and allows strong churning movements that mix food with gastric secretions to form chyme. 6 Parietal cells secrete hydrochloric acid (HCl), which acidifies stomach contents and activates pepsinogen into pepsin for protein digestion. These cells also produce intrinsic factor. 7 Intrinsic factor, produced by parietal cells, binds vitamin B12 and allows it to be absorbed in the terminal ileum. Lack of intrinsic factor can cause pernicious anaemia. 8 Helicobacter pylori infection disrupts the gastric mucosal barrier and increases acid-related damage. This is the most common cause of peptic ulcers. 9 Mucous cells produce mucus and bicarbonate, forming a protective barrier that prevents gastric acid and digestive enzymes from damaging the stomach lining. 10 Stress activates the brain–gut axis, increasing sympathetic activity and gastric acid secretion. This can worsen reflux, gastritis, and dyspepsia, demonstrating the biopsychosocial link in GI disease.
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